1. Field of the Invention
The invention relates to a tray control method, and more particularly to a method for controlling tray ejection and retraction operations in a disk drive.
2. Description of the Related Art
Lately, as the electronic technology advances, optical disks are welcome more and more due to its compact size, high storage capacity and long preserving time for data. Prevalence of the optical disk raises the disk drive to a high demand commodity in the electronic market.
A conventional disk drive generally includes a tray for carrying a disk and a DC motor for moving the tray to the retracted and ejected positions via a gear mechanism, thereby facilitating placing the disk on the tray or removing the disk from the tray. The output force of the DC motor for moving the tray depends on the applied voltage and the voltage level is generally controlled by the firmware of the disk drive.
In general, the force and speed for moving the tray to the retracted and ejected positions depend on the applied voltage to the DC motor and further on the structural connection between the tray and the other interior mechanism, such as a traverse module, clamping mechanism and etc.
In the prior art technology, the engineers at the production factory use try-and-error method to adjust the voltage applied to the DC motor in order to provide stable vibration of the tray during the tray retraction and tray ejection operations in the disk drive. However, in the mass production line, it is relatively difficult to use try-and-error method on each of the disk drives, thereby failing to maintain the structural connection between the tray and the other interior mechanism at the desired position, which, in turn, results in problems.
For instance, when the structural connection between the tray and the other interior components is loose, the force and speed for moving the tray to the retracted and ejected positions is relatively great, which may cause impact between the tray and the interior components, thereby shortening the service life of the disk drive or dropping the disk from the tray at the ejected position. When the structural connection between the tray and the other interior components is tight, the force and speed for moving the tray to the retracted and ejected positions is relatively small, which, in turn, will prolong the retracting and ejecting time for the tray. The result fails to meet the requirement specification of clients.
In the prior art technology, depending on presence or absence of the disk on the tray, the firmware of the disk drive adjusts the voltage applied to the DC motor, thereby altering the output force of the DC motor for moving the tray.
When there is no disk on the tray, the clamping mechanism is located closely to the holding seat so that relatively strong attraction is existed among the interior components. A large force is required to space the components apart or else the tray ejection operation cannot be performed.
When the disk is disposed on the tray, the output force of the DC motor is required to be adjusted appropriately prior to the tray reaching the ejected position. Otherwise, the impact of the tray against the outer casing upon reaching the ejected position will cause dropping the disk from the tray.
Due to the aforesaid reasons, the firmware of the retract-and-eject system in the disk drive plays an important role for determining whether the disk is present or absent from the tray. For instance, the disk is present on the tray but the firmware determines that the disk is absent from the tray, the output force of the DC motor is too large and may drive the tray at an undesired high speed that the disk may drop from the tray during the tray ejection operation. On the other hand, in case the disk is absent from the tray, however the firmware determines that the disk is on the tray, the output force of the DC motor for moving the tray is too small to separate the clamping mechanism from the holding seat so that the tray ejection operation cannot be performed.